Vet’s Voice: Scours, respiratory viruses accompany spring weather
April 6, 2016
The robins in our area seem to have survived the latest snow storms. The temperature changes, high winds and precipitation have been tough on new born calves. We are seeing diarrhea problems and some respiratory problems. Early treatment of these problems is necessary for recovery.
Our evaluation of these problems have highlighted pathogens we don't often expect in our area. We have diagnosed corona virus in many scour outbreaks through the years. This year we have seen the diagnosis of corona virus in several respiratory samples from young calves. We have seen problems in weaning calves with respiratory issues. It has usually been associated with BRSV (bovine respiratory syncytial virus) infections. European dairy models have indicated the combination of these two viruses in many scenarios.
The jury is still out on whether the enteric form of corona virus (scours) crosses over to cause respiratory symptoms. Viruses generally disrupt the lining of the lungs and respiratory tree allowing bacteria to enter and cause severe respiratory signs. There is no vaccine currently available for respiratory corona virus, although I am told corporate America is researching possibilities. I know of instances in the field when oral vaccines for scour protection have been injected and used to attempt to produce immunity. In young calves we hope they gain immunity to corona virus through the colostrum by immunizing the cows with corona vaccine. This appears to be good science, but there is no data to support any of these protocols for respiratory infections.
The wet weather has added to the Cryptosporidia problems we are seeing in calves. Most herds in our area have animals carrying Crypto. As conditions deteriorate the shedders deposit the organism on bedding and into puddles and standing water. The calves then contract the organism from suckling a soiled udder or drinking contaminated water. The common scenario in a normal calving season is a moderate scour at seven to ten days. If a storm or stressor hits, several animals will become very ill, scour, and may become wobbly. Usually you will see some flecks of blood in the loose feces. Treatment is tough and there are no silver bullets (sure fire cures). The best is supportive and supplemental care. Many times after recovery a stress may cause a relapse. Our best treatments involve prevention to remove shedders. Many mineral supplements fed to cows will reduce your problems. Probiotics are also useful in treatment and during recovery.
Many time clients ask, "What's new in animal health?" It is great when we can expound on a new product, management procedure, or treatment. Sadly, there are still many common problems which need more research for answers, and there appears to be little funding available for these problems. Consult with your veterinarian, nutritionalist, or extension specialist to search out answers for the problems in your herd. Careful examination and consultation will bring healthier calves into your herd.